Income Taxes - Components of Federal and Foreign Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets related to:
Pensions	$ 1,985	$ 2,994
Accrued compensation and benefits	957	926
Contract accounting methods	470	392
Foreign company operating losses and credits	40	51
Other	473	509
Valuation allowance	(15)	(13)
Deferred tax assets, net	3,910	4,859
Deferred tax liabilities related to:
Goodwill and intangible assets	401	363
Property, plant and equipment	518	481
Exchanged debt securities and other	709	547
Deferred tax liabilities	1,628	1,391
Net deferred tax assets	$ 2,282	$ 3,468